Caeleb Dressel claimed his fourth Tokyo gold and earned the title of world's fastest swimmer Sunday with an Olympic-record 21.07 seconds in the 50m freestyle final.
The American was untouchable in an event he has dominated in recent years, hitting the wall ahead of France's Florent Manaudou (21.55), who won gold at London in 2012 and silver at Rio 2016.
Brazilian Bruno Fratus (21.57) was third.
Dressel had his usual powerful start off the blocks and no one was going to stop him in the one-lap race as he continues to threaten Cesar Cielo's 2009 world record of 20.91.
It was his fourth gold of the Games after winning the 100m butterfly in a new world record, the 100m freestyle and the men's 4x100m relay.
He is expected to suit up again for a crack at a fifth later Sunday in the mixed 4x100m relay final.
McKeon wins women's 50m freestyle gold
Australian Emma McKeon swept to her third Tokyo gold and sixth medal overall Sunday when she dipped below the magic 24-second mark to win the women's 50m freestyle title.
The 27-year-old hit the wall in a new Olympic-record time of 23.81 ahead of Swedish world record-holder Sarah Sjostrom (24.07) and Denmark's defending champion Pernille Blume (24.21).
McKeon also lowered the Olympic record in both the heats and semi-finals, and there was no stopping her as she added the one-lap sprint to her 100m title.
She also won gold in the 4x100m relay while taking bronze in the 100m butterfly, 4x200m relay and 4x100m mixed medley relay for a hugely successful Olympics.
McKeon will also suit up for the mixed 4x100m medley relay later Sunday.
China's Gong wins women's shot put
China's Gong Lijiao lived up to her pre-Olympic form by winning gold in the women's shot put on Sunday.
Gong managed a personal best of 20.58 metres on her sixth and final attempt, having led the competition from her opening effort of 19.95m.
American Raven Saunders took silver with 19.79m, while New Zealand veteran Valerie Adams, in her fifth Olympics, was left delighted as she claimed bronze (19.62) to go with golds in 2008 and 2012, and silver in 2016.
Finke wins 1500m to seal distance double
America's Robert Finke secured the Olympic distance double Sunday by winning the men's 1500m gold medal to go with his 800m title.
The 21-year-old delivered a devastating final 50m to pull clear of a tight field in a race that was neck-and-neck from the off.
Finke touched first in 14mins 39.65secs ahead of Ukrainian Mykhailo Romanchuk (14:40.66) and Germany's Florian Wellbrock (14.40.91).
Gregorio Paltrinieri would ordinarily have been favourite as defending champion and second fastest ever behind China's banned Sun Yang.
But the Italian was struck down with glandular fever in June, hampering his built-up, and he could only finish fourth.
Australia win women's 4x100m medley relay gold
Emma McKeon made Olympic history Sunday in helping Australia upset two-time defending champions the United States to soar to the women's 4x100m relay gold medal Sunday.
Their team of Kaylee McKeown, Chelsea Hodges, McKeon, and Cate Campbell touched in a new Olympic record 3mins 51.60secs ahead of the US in 3:51.73 and Canada in 3:52.60.
It was McKeon's seventh medal in Tokyo, a feat no other female swimmer has ever achieved at a single Olympics.